(1). Field of the Invention
This invention relates, in general, to a novel means for fastening two abutting members together. More particularly, the invention relates to a novel mounting curb assembly for rooftop packaged air conditioning units which can be constructed from modular components by novel interlocking fastening means.
(2). Description of the Prior Art
Mounting curbs or assemblies, sometimes called "roof curbs," have been used now for many years by those in the air conditioning industry as a foundation or support member for packaged air conditioning units mounted on the tops of roofs of buildings. The roof curb assembly comprises, in general, two side walls or panel members and two end walls or panel members connected together at their ends to form a rectangular framework.
The roof curbs were, in earlier days, constructed by welding the ends of the panels together to form corners. Nevertheless, such was unsatisfactory for a number of reasons. One reason was that the roof curb components were assembled together off-site and welded. This, of course, resulted in difficulty in handling and raising the roof curb to the roof of the building on which it was to be installed.
Later, the roof curb components were provided in modular side and end panel members and assembled together at the work site. Thus, the panel members were sometimes interconnected at their ends by means of rivets or threaded fasteners. This proved somewhat better but still was not without some disadvantages. First of all, as can be appreciated, the assembly of the roof curb components was somewhat labor intensive. There were a considerable number of threaded fasteners involved which had to be located in the curb members by the installer and then screwed together. Moreover, the handling of such fastening means often resulted in some being dropped and lost, and need then for obtaining further such fastening means, to complete the job.
More recently, however, the assembly of the roof curb modular side and end walls or panel members has been somewhat improved. This has resulted because, in part at least, with the means now used for fastening two such panel members together to form a corner of the roof curb, one of the fastening members is provided integral to the ends of a panel member. Moreover, there are no screw or threaded fasteners with which to be concerned. Exemplary of such fastening means for interconnecting roof curb panel members together are those disclosed in U.S. Pat. Nos. 4,781,008; 5,016,406; and 5,188,333.
In U.S. Pat. No. 4,781,008, there is disclosed a frame assembly for a building opening which comprises four curb or wall elements connected together. Each of the corners of the frame assembly is formed by connecting an end plate of a wall element to one face of a vertically disposed corner post having a square cross-section, so that the wall elements are ninety degrees to one another. Each end plate is provided with two spaced-apart apertures located in vertical disposition one above the other. The two sides of the corner post at a right angle to one another are each provided with two, vertically disposed, spaced-apart fingers. Thus, when assembled together, the two faces of the corner post abut the end plates of two of the wall elements and the two fingers on each surface of the corner post engage with the apertures in the end plates.
U.S. Pat. No. 5,016,406 discloses an interlocking joint for a roof curb which comprises a male joint member secured to the inner face of the end of a roof curb side section and a female joint member secured to the inner face of the end of a roof curb end section to be joined thereto. The male joint member is constructed to have an "L" shape, the stem of the "L" fastened to the side section being jogged so that the lower portion of the stem defines a space with the inner face of the side section. The female joint member is defined by an inner and outer face, which together form between them a receptacle which is adapted to receive the male joint member. The outer face of the female joint is of an "L" shape construction. The inner face is a leg which has a jogged shape, one portion of the jogged shape abutting the stem of the "L" shape and being fastened to it and to the inner face of the roof curb end section. The other part of the jogged shape defines a space between the jogged shape and the stem of the outer face of the female joint. This space is adapted to receive the foot of the "L" shaped male member. Although this interlocking joint is quite satisfactory in certain respects, its use is not without certain disadvantages. One disadvantage is that the members making up the fastening means must each be manufactured apart from the side and end sections, requiring additional time and expense. Then, the members must be securely fastened, for example, by spot welds to a respective roof curb section.
U.S. Pat. No. 5,188,333 discloses a supporting frame for an air conditioning unit installed on the roof of a building. The frame comprises two spaced-apart, parallel side walls interconnected at their respective ends to the ends of two spaced-apart, parallel end walls. The side walls are each provided at their ends with perpendicularly disposed side flanges. In each of these flanges there is provided a plurality of fasteners, i.e. a tongue and an accompanying latch punched out of the flange. These fasteners are provided in pairs and in vertical alignment superposed one above the other. Each of the end walls is provided with two rows of slots or openings, each row of a like plurality of slots as the fasteners in the side walls. The two rows are spaced apart so that when an end wall is assembled with a side wall the slots will be in mating engagement with the fasteners. In providing the side walls in assembly with the end walls, the tongues on the flanges of the side wall slip into respective slots and in engagement with the edge of the slot. The length of the slot is such that when the tongue fully engages with the slot perimeter, the latch snaps into place in the slot. Thus, the free end of the latch engages with the edge of the slot and prevents the end wall from being moved so as to be free of engagement with the tongue.
Another roof curb of which we are aware involves the providing of means integrally adjacent the ends of two panel members which are to be connected together to form a corner. Thus, in the one panel member, adjacent the vertically disposed linear edge thereof, there are provided two spaced-apart rectangular-shaped openings, one above the other. The other panel member is provided with a flange at its end which extends inwardly and perpendicular to the panel. In the flange are provided two spaced-apart tongues or elongated members, each of which is connected at its base to the panel member. Each tongue lies in a plane parallel to that defined by the panel so that a space exists between the tongue and the panel member. The tongues are so located on the flange that when the flange is placed into contact with the other panel member a portion of that panel member which surrounds the openings can be captured in the space between the tongue and the other panel member. Although this roof curb is satisfactory to a certain extent, its use presents certain problems. One problem involves joining a side panel member and end panel member together in forming the fourth corner. This is made somewhat difficult due to the fact that the means for fastening the two panel members together to form the corner are provided in the panel members themselves, and the fact that the panel members are somewhat inflexible at this point of assembly.
Also known to us is a so-called "hinge roof curb." In this construction, the corner assembly of a roof curb basically comprises a butt hinge such as used in mounting a door. Thus, the end of a curb side section is integrally provided with one part of the hinge. The end of the end section of the curb is integrally provided with the mating part of the hinge. The curb end and side sections are assembled together so that the hinge parts mate together and then the "hinge" pin is driven downwardly through the openings in the mating sections. Thus, the end section is joined or interlocked to the side section and a corner of the roof curb is formed. After the four corners are assembled together, the curb is checked to be sure it is in "square." This is done by measuring diagonally from each of the opposite corners. This dimension should be the same for each direction. This fastening means, however, suffers from several disadvantages. First of all, the parts of the "hinge" must be in good alignment with one another as anyone who has taken a door down and then put it up again is readily aware.
Thus, there is still the need for a roof curb assembly which comprises modular components, i.e., side and end walls or panel members, of simple construction and which can be assembled together with greater ease.